Research Publications

Molecular and histopathological detection of vibrio harveyi associated with mortality in Asian sea bass cultured in Sri Lanka

2026-06-10T00:00:00Z

Molecular and histopathological detection of vibrio harveyi associated with mortality in Asian sea bass cultured in Sri Lanka Velichor, Sakajamary; Mohamed Fouzi, Mohamed Naleem; Jagoda, Samanthika; Jinadasa, Rasika; Musthafa, Muneeb Mohamed; Thassim Marikar, Faiz Mohideen Mohamed Asian sea bass (Lates calcarifer), commonly known as barramundi, is an economically important food fish inhabiting coastal and brackish waters. In Sri Lanka, demand for commercial and recreational fishing has increased due to its mild flavor and culinary versatility. However, disease outbreaks pose significant challenges to aquaculture production, particularly in cage culture systems. This study investigated the causative agent of mass mortality events in Asian sea bass farms in Trincomalee, Sri Lanka. Fish exhibiting clinical signs, including skin ulcers, fin rot, exophthalmia, and lethargy, were collected for examination. Samples from the kidney, liver, and spleen were cultured on Tryptic Soy Agar (TSA) and Thiosulfate Citrate Bile Salts Sucrose (TCBS) agar at 37 °C for 24-48 hr. Isolates produced small to medium, round, convex colonies on TSA and green colonies on TCBS. Biochemical characterization revealed Gram-negative, oxidasepositive, catalase-positive, motile rods that fermented glucose without gas production. Molecular identification using 16S rRNA polymerase chain reaction confirmed the pathogen as Vibrio harveyi with 99.44% similarity to strain CP014038.2. The sequence was deposited in GenBank (accession number OR351233). Histopathological examination revealed tubular injury, necrotic epithelial cells, and macrophage-lymphocyte infiltration in liver and kidney tissues. This study confirms that Vibrio harveyi is strongly associated with Vibriosis, causing mass mortality in Asian sea bass cage culture in Trincomalee. These findings provide essential baseline data for developing effective disease prevention and control strategies in Sri Lankan aquaculture systems.

Laying hen welfare in intensive farming system in Sri Lanka: a five freedoms approach

2026-05-23T00:00:00Z

Laying hen welfare in intensive farming system in Sri Lanka: a five freedoms approach Athukoralaa, A. I. C. D.; Nikzaada, R. M.; Niwanthakab, R. M. D.; Musthafaa, Muneeb M.; Marikar, Faiz M.M.T. Animal welfare refers to the state of an animal's physical and mental health as well as its well-being, humane treatment, and appropriate care. The purpose of this study was to evaluate the welfare of a flock of laying hens on an intensive farm in Kundasale, Sri Lanka's mid-country. The Five Freedoms and welfare indicators, including as behaviour, environmental circumstances, and production statistics, were used to evaluate the overall welfare of the farm. The Five Freedoms and behaviours like eating, drinking, relaxing, strolling, dust bathing, foraging, excretion, and flapping were among the welfare indicators that exhibited notable variations. The Kundasale farm in Sri Lanka was categorised as a "Normal farm" with an overall wellbeing score of 44.73%, which is between 40 and 60%. In terms of meeting the needs of the intensive broiler breeder farm, the results of this assessment contributed to enhancing flock welfare standards and improvements in the poultry farming practices of this farm

Assessment of locally available substrates for enhancing sustainable moina macrocopa production

2026-04-30T00:00:00Z

Assessment of locally available substrates for enhancing sustainable moina macrocopa production Kumari, S.; Fouzi, M. N. M.; Musthafa, M. M.; Thaiuba, A.; Marikar, F. M. M. T Artemia is commonly used to feed fish larvae, but its high cost, specific hatching conditions, and limited local availability make it less accessible in developing countries. Moina macrocopa, a nutritionally rich and widely distributed zooplankton, offers a promising low-cost alternative, though knowledge on its large-scale production and feeding techniques remains limited. The present study was designed to evaluate the effect of different animal manures and food waste as substrates in the mass culture of Moina macrocopa, to identify the most effective and sustainable method for maximizing its production in terms of both quality and quantity. To assess the efficacy of various locally accessible substrates for the sustainable mass culture of Moina macrocopa, three laboratory experiments were carried out. Four treatments soy milk plus poultry manure, rice bran plus fish meal, cow dung plus yeast, and cow dung alone were applied to a pure culture of M. macrocopa that was fed with Chlorella sp. Moina population counts were taken every day for seven days throughout each experiment, which was conducted under controlled circumstances with constant aeration. The combination of yeast and cow dung produced the greatest average population (228.16 individuals per 600 ml) among the treatments, suggesting that this substrate is the most efficient and sustainable choice for producing Moina macrocopa on a wide scale.

Analysis and risk evolution of floods and cyclones in Sri Lanka from 1975 to 2025 towards resilient strategies

2026-05-05T00:00:00Z

Analysis and risk evolution of floods and cyclones in Sri Lanka from 1975 to 2025 towards resilient strategies Partheepan, Kulasegaram; Musthafa, Muneeb M.; Bhavan, Thangamani; Acharjee, Shukla; Nath, Biswajit Sri Lanka has witnessed a struggle with floods and cyclones, transitioning from occasional emergencies to persistent and growing threats. This study provides the first consolidated long-term temporal analysis that uniquely integrates 50 years (1975–2025) of meteorological trends with a parallel critical evaluation of monitoring technology evolution and institutional governance efficacy. Using Mann-Kendall trend analysis and Pettitt change-point detection, key statistically significant trends were demonstrated: cyclonic disturbance frequency increased from 1.3 to 4.1 systems/year (p<0.001), and extreme rainfall intensity rose by +12.2 mm/decade (p<0.05). Change-point analysis identified 1998 as a statistically significant inflection year (Pettitt test, p<0.05), after which the cyclonic rainfall contribution increased by 18–25% in the northern and eastern provinces. While monitoring capabilities have advanced from rain-gauge dependence (pre-1990) through the satellite era (1990– 2000 s) to real-time Earth observation integration (post-2015), a critical institutional gap remains. This “last-mile” problem is operationally defined as the persistent gap between the forecast lead time and actual evacuation completion times, revealing that a 6-fold increase in forecast lead time (from 12 to 24 h in 1975–1990 to 72– 168 h in 2015–2025) has yielded no proportional improvement in evacuation times, which remain stagnant at 18–36 h. Based on this analytical evidence of persistent institutional failure despite technological progress, this study conceptually proposes an integrated Sri Lanka Multi-Hazard Risk Monitoring and Decision-Support Platform (SL-RISK) that couples technical data integration with community-embedded monitoring, impact-based forecasting, and pre-arranged institutional response mechanisms, outlined with a phased 18–36-month implementation roadmap. Without addressing this governance-technology mismatch, technological advances remain underutilised, perpetuating cycles of preventable disaster losses among vulnerable populations.